A Snooper is someone who digs through things that they shouldn't, aren't theirs and they have *NO BUSINESS* with and who then gets all bent out of shape over what they find.
My X looked through my phone and just started deleting phone numbers. Fucking hate Snoopers.
He got back together with his X. After she was moved back into his house, she turned Snooper and read his e-mail over the 6 months they weren't dating/talking/hated-each-other.
She went Snooper on his Facebook to find the girl he'd been fucking, or maybe just knows, or could even be related to. She couldn't tell from Facebook but she was *PISSED* anyway.